1. Field of the Invention
The invention relates to dryer felts and more specifically relates to dryer fabrics for the manufacturing of fine grade paper.
2. Brief Description of the Prior Art
The art is replete with descriptions of dryer felts and dryer felt fabrics; see for example U.S. Pat. Nos. 2,098,993; 2,506,667; and 3,248,802. However, the heretofore available felts have not been completely satisfactory for all purposes. For example, in the manufacture of relatively fragile papers such as condenser, cigarette and Bible stocks, one must employ dryer felt having a very flat, soft face. Prior to our invention, such dryer felts were produced in an endless form from soft, spun yarns. They could be made from flat woven fabrics but the continuous soft face quality desired was interrupted by bulky seams, as known in the dryer felt industry, which would mark the sheet of paper being conveyed. This product is less advantageous because it is necessary to dismantle substantial proportions of the paper machine to install the endless felt and to replace felts. If it were possible to employ a seamed dryer fabric whose surface is not interrupted by a bulky seam area and is soft throughout its entirety it would be possible to install the felts without dismantling the paper machine.
The fabric of our invention is flat woven and has all of the surface characteristics desired for a dryer felt used in the manufacture of relatively fragile papers such as condenser, cigarette, Bible and like stocks. In addition, the fabric has the structural integrity required to join together the ends of the fabric in a conventional pin seam. Dryer felts prepared from the dryer fabric of our invention combine the properties of an all monofilament dryer felt including the ease of guiding, superior strength and pin seam capabilities, with that of an endless woven and/or needled dryer felt having a smooth, non-marking surface. In a preferred embodiment of the invention, a pin seam (as known in the dryer felt industry) may be incorporated into the monofilament base fabric and a spun yarn flap can then be created over the pin seam area. The flap gives the appearance of and acts like a completely smooth surface. Without the flap, an opening in the fabric would be present at the pin seam area. It is the fact that there is a smooth yarn surface, even at the pin seam area, that enables the seamed dryer felt of our invention to be used in place of an endless dryer felt of the prior art.